The present invention relates to a sheet feeding apparatus for feeding a sheet to a predetermined position. More specifically, the present invention relates to a sheet feeding apparatus having register means for correcting a skew of a sheet by contacting a leading edge of the sheet for alignment.
In a conventional sheet feeding apparatus, a draw roller picks up sheets stacked on a stacking tray. A separating device composed of a sheet feed roller and a separation member separates the sheets into a single sheet, and sends the single sheet to a pair of register rollers. The sheet feed roller feeds the sheet to abut against a nipping portion of the register rollers to form a loop having a predetermined size for correcting a skew of the sheet.
Japanese Patent Publication (Kokai) No. 2000-203729 has disclosed a sheet feeding apparatus in which a sheet is transported for a predetermined distance to a pair of register rollers for correcting a skew when sheets having a same size are stacked on a stacking tray.
When such a sheet feeding apparatus feeds the sheet having the same size, the sheet is transported in a state that side regulating plates on the stacking tray regulate both side edges of the sheet in a width direction. Therefore, it is possible to reduce a variation in the skew in the width direction. When the sheet feeding apparatus feeds sheets having different sizes, it is difficult to regulate a sheet having a size other than the maximum size with the side regulating plates. As a result, when the sheet feeding apparatus feeds the sheets having the different sizes, as opposed to the case of feeding the sheets with the same size, it is difficult to reduce the variation in the skew and properly correct the skew depending a size of the sheet.
In particular, in a sheet feeding apparatus in which the sheets are stacked based on a center of the sheets in the width direction, a draw roller and a sheet supply roller are arranged at a center portion of the apparatus in the width direction of the sheet. Accordingly, when the sheet having a size different from the maximum size is fed, the draw roller and sheet feed roller contact the sheet at a position shifted from the center thereof in the width direction, resulting in a large skew with great frequency. Therefore, it is possible to damage the sheet or feed the sheet improperly, thereby causing a problem.
In view of the problems described above, the present invention has been made, and an object of the present invention is to provide a sheet feeding apparatus in which a skew of a sheet can be corrected even when the sheet stacked on a stacking tray is not regulated properly with side regulating plates.
Further objects and advantages of the invention will be apparent from the following description of the invention.